The technique of computerized or computer-assisted tomography was developed in approximately 1972 and involves a diagnostic X-ray system designed for neuroradiological investigation. Different techniques and instrumentations have been provided for computer-assisted tomography to accurately probe deep-seated brain lesions. In some instances, the CT scan is used for guidance and in other instances, the CT scan is combined with stereotactic techniques. In applicant's U.S. Pat. No. 4,463,758, a stereotactic frame is disclosed.
Generally in the stereotactic technique, calculations of three coordinates are required: namely, the X coordinate (the lateral), the Y coordinate (posterior-anterior distance) and the Z coordinate (the vertical heights from the reference baseline). In the stereotactic system described herein, the probe holder and the axis of rotation of the arc are placed in the same CT plane as the target using the laser positioning light thereby eliminating the need to calculate the Z coordinate (the distance from the baseline of scanning to the target). In addition, the utilization of the invention described herein enables one to directly measure the X and Y coordinates from a single picture without the need for special computer programming, calculations or special atlases.
It is therefore a principal object of the invention to provide an improved stereotactic system.
A further object of the invention is to provide an apparatus for performing surgical procedures through a patient's skull to a target within the skull by utilizing a computer-assisted tomography scanner.
Yet another object of the invention is to provide an apparatus of the type described which utilizes a planar approach to CT stereotaxis which enables the measurement of the coordinate to be done in one plane which is in the same vertical plane of the CT picture in which the target is located.
Still another object of the invention is to provide an apparatus of the type described wherein the center of the probe holder and the circular attachment are aligned in the same plane which enables the two elements to be aligned in the same CT plane as the target utilizing the vertical positioning light of the CT scanner.
Still another object of the invention is to provide an apparatus of the type described wherein targets within the skull can be approached from the lateral position.
Still another object of the invention is to provide an apparatus of the type described including a movable head holder mounted thereon to enable the head holder to be selectively moved to a position out of the plane of the CT scanner to eliminate any possibility of artifact.
Still another object of the invention is to provide a system which utilizes the top surface of the base platform and the central marker on the base platform as reference markers so that the apparatus may be used with any CT scanner.
Still another object of the invention is to provide an apparatus which is compatible with nuclear magnetic resonance scanners.
Yet another object of the invention is to provide an apparatus which may be easily removed from the table of the CT scanner.
These and other objects will be apparent to those skilled in the art.